Heat induced expression during embryogenesis causes disruption of head involution, elements of the head skeleton are severely reduced in size or missing. Anterior to thoracic segment 1 the embryo is expanded due to the non-involuted head segments that are transformed towards more posterior segmental identities (evidenced by the thoracic/abdominal denticles). Heat induced expression during early third instar partial antenna to leg transformation in adults, the arista is replaced by tarsal leg segments. Induction during late third instar causes lack of ocellar bristles, ocelli and postvertical bristles. Also embryos exhibit a Ctx-like transformation, dorsal posterior head partially transformed toward dorsal thorax.